> Because the power suppliers for EY IM heater seemed to be in error mode, I restarted them. 

このエラーは入力AC電源の電圧低下で発生する現象です。

最小85Ｖacから使用可能なので電圧がこれよりも低下したということになります。

まずは電源の品質と環境を確認することをお勧めします。


> Because the power suppliers for EY IM heater seemed to be in error mode, I restarted them. 

This error is caused by a voltage drop in the input AC power supply.
Since a minimum of 85 Vac is available, this means that the voltage has dropped below this level.
I recommend that you first check the quality of the power supply and the environment.